Nowadays, a refrigerant R410A has been increasingly used as a refrigerant charged in a refrigerating cycle of a refrigerator/air conditioner, etc. The refrigerant R410A improves efficiency of the refrigerator/air conditioner. This improvement makes it possible to decrease electrical power consumption and reduce an amount of carbon dioxide produced during power generation. In addition, measures against refrigerant leakage are used to reduce refrigerant emission, thereby contributing to prevention of global warming.
The refrigerant R410A, however, has a high GWP (global warming potential). Accordingly, in view of further prevention of global warming, it is desirable to use in a refrigerating cycle device a refrigerant with a lower GWP than the refrigerant R410A. A refrigerant R32 seems to be a refrigerant candidate.
This refrigerant R32 is slightly combustible. In order to reduce an amount of refrigerant leakage in the rare case of refrigerant leakage, it is preferable to reduce an amount of refrigerant charged in a refrigerating cycle as much as possible.
In addition, the refrigerant R410A may be switched to the refrigerant R32 to decrease the diameter of a connection pipe (refrigerant pipe) connecting an indoor machine and an outdoor machine. This makes it possible to not only decrease an amount of refrigerant charged but also to reduce a usage of copper, which is a material for the connection pipe. Further, the above enables connection pipe workability to increase during air conditioner installation, etc.
JP2001-248941A (Patent Literature 1) and JP2002-89978A (Patent Literature 2) disclose conventional technologies related to refrigerating cycle devices using the above refrigerant R32.
In the above Patent Literature 1, a refrigerating cycle device using a refrigerant R32 has fixed pipe diameters of a liquid-side connection pipe and a gas-side connection pipe.
In addition, in the above Patent Literature 2, a refrigerating cycle device using a refrigerant R32 has a fixed amount of refrigerant charged in a refrigerating cycle.